Ozone generator

ABSTRACT

An improved ozone generator formed from two groups of spaced, interleaved, relatively small reactor plates in a housing. Each of the plates is cooled by a coolant passing through the interior thereof. The coolant is a refrigerant flowing through a refrigeration system for which the plates define the evaporator. Each plate has a ceramic outer coating which provides a dielectric therefor and protects the plate from corrosion. Improved support means for each group of plates includes a pair of tubular mounts formed from fittings which convey the refrigerant to internal passages in the plates, provide the electrical connections thereto, and permit the plates to be coupled together as a modular unit so that the plates can be leak-tested before being placed in the housing. Improved fluid distribution means is provided at the inlet and outlet ends of the housing to assure uniform flow of air into the housing and uniform flow of air and ozone out of the housing.

lJite States Patent [191 Emigh et al.

i 1 OZONE GENERATOR [75] Inventors: Willard F. Emigh, El Dorado Hills;

Rudi Beichel, Sacramento, both of Calif.

[73] Assignee: Aerojet General Corporation, El

Monte, Calif.

[22] Filed: Mar. 13, 1974 {2|} Applv No.: 450,698

[52] U.S. Cl. 250/541, 250/532 [5 1] int. Cl C0lb 13/12 [58] Field ofSearch r. 250/532-538, 250/540, 541

[56] References Cited UNITED STATES PATENTS 3.404.778 7/1946 Allison250/541 X FOR ElGN PATENTS OR APPLICATIONS 1101.375 3/l96l Germany250/532 Primary Examiner-John H. Mack .lvsl'slanl Examiner-AaronWeisstuch Mmrney Agent. or FirmTownsend and Townsend OZONE OUTLET [451Mar. 18, 1975 [57] ABSTRACT An improved ozone generator formed from twogroups of spaced, interleaved, relatively small reactor plates in ahousing. Each of the plates is cooled by a coolant passing through theinterior thereof. The coolant is a refrigerant flowing through arefrigeration system for which the plates define the evaporator. Eachplate has a ceramic outer coating which provides a dielectric thereforand protects the plate from corrosion. Improved support means for eachgroup of plates includes a pair of tubular mounts formed from fittingswhich convey the refrigerant to internal passages in the plates, providethe electrical connections thereto. and permit the plates to be coupledtogether as a modular unit so that the plates can be leak-tested beforebeing placed in the housing. Improved fluid distribution means isprovided at the inlet and outlet ends of the housing to assure uniformflow of air into the housing and uniform flow of air and ozone out ofthe housing.

23 Claims, 10 Drawing Figures I8 7| INLET COOLANT I ..THHEUHAR I 8|SY5FIG .6 20-\ SHEET 2 11 3 M 22 22 ifig H h a H I52 AIR AND AIR L OZONEOUT 1 0 OZONE FIG. no GENERATOR 7| 82 (EVAPORATOR HEAT EXCHANGEREXPANSION |2| COMPRESSOR ||2 "7 -ERE0N IN FREON OUT --WATER OUTCONDENSER OZONE GENERATOR This invention relates to improvements in theproduction of ozone and, more particularly, to an improved ozonegenerator which is more efficient in operation than conventional ozonegenerators.

BACKGROUND OF THE INVENTION Ozone generators have been constructed inthe past with a plurality of spaced, interleaved electrode plates,whereby an electric field established between the plates causes ozone tobe generated in the space between the plates. The ozone is then drivenout of such spaces by incoming gas and is utilized at a remote location.Various types of dielectrics have been used with such electrode plates.Also, the way in which the dielectrics are mounted to or placed adjacentto the plates has been the subject of a number of different disclosures.Typical of these disclosures are the following US. Pat. Nos. 2,429,152;2,260,831; 2,309,616; 3,010,892; 3,622,492; 3,081,215 and 3,654,126.

For the most part, these patents disclose the use of a dielectriccoating on one face of each pair of adjacent reactor plates. When theplates are assembled, the coatings face each other and are maintained inspaced relationship by at least a pair of dielectric posts which spanthe distance between the coatings. As a result, each pair of adjacentreactor plates are separated by a very short creep distance which isdefined as the distance through which electric charges from one platecan creep toward and onto the next adjacent plate when the two platesare at different potentials. In the aforesaid patents, this distance ismeasured in fractions of an inch because the reactor plates are quiteclose together because the dielectric posts are very short in length.

The use of the aforesaid dielectric posts requires frequent maintenanceto keep the posts clean. They acquire deposits on their outer surfacesdue to impurities in the air passing between the plates. Theseimpurities provide the path by means of which charges creep from oneplate to another. When this creeping occurs, stresses are set up in thedielectric coatings which eventually cause them to break down so as toresult in a massive arc-over between the plates.

Other disclosures have shown that the reactor plates of an ozonegenerator can be hollow for receiving a coolant, such as water or oil,passing therethrough to cool the same during operation. Such disclosuresinclude the following US. Pat. Nos. 2,118,969; 3,364,129; and 3,671,417.For the most part, the plates of these disclosures are bulky and heavythereby requiring considerable space and complicated support structure.

Conventional ozone generators have generally not been provided withmeans for controlling the way in which air is directed into the spacesbetween the reactor plates and the way in which the ozone is removedfrom such spaces. Inlet air enters the reactor region at one locationand must distribute itself merely by backpressure built up in suchregion due to a single, relatively small outlet. With no such control,incoming air is not uniformly distributed in the spaces so that certainportions of the spaces lack sufficient air for efficient ozoneproduction while other portions of the spaces have an overabundance ofair.

In a conventional ozone generator using Coolants, it is required thatthe coolant be lowered in temperature after passing through thegenerator. This requires a refrigeration system whose evaporator is inheat exchange relationship to the coolant coming from the generator.Thus, both a coolant itself and some type of cooling apparatus, such asa refrigeration system with its refrigerant, is required to cool thereactor plates of an ozone generator when the plates have fluid passagestherethrough.

Some types of conventional ozone generators cool only every other plate.This causes high temperatures in the regions between the electrodeplates, resulting in minimal ozone production. Thus, relatively largeplates are required to obtain a worthwhile ozone yield. In otherconventional generators, only two electrode plates are used; thus, onlyone side of each plate is used for ozone production.

SUMMARY OF THE INVENTION The present invention is directed to animproved ozone generator which overcomes the problems mentioned abovewith respect to conventional ozone generators. By virtue of theimprovements of the present invention, ozone can be more efficientlygenerated at a lower cost, yet the generator can be substantiallymaintenance-free and can have any desired number of reactor platesdepending upon the desired capacity of the ozone generator.

One of the features of the ozone generator of this invention is the useof two groups of reactor plates, with each plate being relatively smallin size and provided with internal passages to permit a refrigerant of arefrigeration system to pass therethrough for cooling the same. Eachplate carries its own dielectric by virtue of a ceramic coating coveringits entire outer surface. Thus, the plates of one group can beinterleaved with and cantilevered relative to the plates of the othergroup without contacting the same. Thus, the plates need not berelatively large and they can be quite close together as there is asubstantially infinite creep distance between the plates. Since theplates can be relatively small in size and close together, they can behoused in a minimum of space to provide a small, neat package forgenerating ozone.

The creep distance of the ozone generator of this invention is quitelong because of the absence of dielectric posts spanning the distancebetween the plates as in the prior patents mentioned above. Thisdistance in the present invention is measured along a path extendingbetween the mounts of each pair of adjacent plates. This path,therefore, includes a stretch of the housing or support to which themounts are secured. Such a stretch is quite long, i.e., of the order ofseveral inches. Moreover, this path is remote from the plates and theair space therebetween so that the need for frequent cleaning andremoval of foreign material along the path is eliminated. Thus, thedielectric coatings on the plates are not subjected to stresses as theyare in the prior patents so that the operating life of the plates isgreatly prolonged and the danger of arc-over is virtually eliminated.

The plates of each group are coupled together as a modular unit by apair of tubular mounts which convey the refrigerant to the internalpassages of the corresponding plates and which serve as the electricalconnections thereto. Thus, the modular units defining the two groups ofplates can be leak-tested before being placed in a housing within whichozone is to be generated.

Another feature of the present invention is the fact that the two groupsof reactor plates form a unit which substitutes as the evaporator for arefrigeration system whose refrigerant passes into the internal fluidpassages of the reactor plates in heat exchange relationshp thereto. Therefrigerant is Freon which is electrically non-conductive. The use of arefrigeration system eliminates the need for additional flow structure,such as pipes, condensers and the like when, for instance, water or oilis used as a coolant. Also, a portion of the refrigerant can be used topre-cool the air which is directed toward and into the spaces betweenthe reactor plates.

A further feature of the present invention is the use of fluiddistribution and control means at the inlet and outlet ends ofthehousing containing the reactor plates. The inlet control means permitsair entering the housing to be uniformly distributed to the spacesbetween the reactor plates to increase the efficiency of productiontherebetween. The outlet control means provides a small, uniformback-pressure in the spaces between the plates to assist in distributingthe incoming air in such spaces.

The primary object of this invention is, therefore, to provide animproved ozone generator operable to produce ozone more efficiently andsafely than is capable with ozone generators of conventionalconstruction, yet the generator will have a long, substantiallymaintenance-free operating life.

Another object of this invention is to provide an improved ozonegenerator comprised of a plurality of spaced interleaved reactor plates,with each reactor plate having fluid passage means therein and having auniform ceramic coating on its entire outer surface, whereby arefrigerant can be directed through the plates to cool the same and thecoating on each plate provides the dielectric therefor and permits theuse of relatively inexpensive metals as the material for the electrodeplates.

A further object of this invention is to provide an ozone generator ofthe type described wherein a refrigerant of a refrigeration system isdirected through the internal fluid passages of the reactor plates tocool the same and to avoid the need for conventional coolants, such aswater or oil, to thereby minimize the cost of maintaining the ozonegenerator while keeping its capacity relatively high.

Still another object of this invention is to provide a generator forozone of the type described wherein the generator has improved fluidflow distribution and control means at the inlet and outlet end of thehousing thereof to distribute the incoming air and to collect theoutgoing ozone more efficiently to thereby assure efficient operation ofthe generator irrespective of its capacity.

A further object of this invention is to provide an ozone generatorhaving two groups of spaced, interleaved plates having ceramic coatingson their entire outer surfaces wherein all plates are cooled so thatboth sides of the plates can be used to produce ozone, the plates can berelatively small in size and close together to assure optimum ozoneproduction, and the plates can be housed in a minimum of space.

Other objects of this invention will become apparent as the followingspecification progresses, reference being had to the accompanyingdrawings for an illustration of the invention.

In the drawings:

FIG. 1 is a perspective view of an ozone generator of this invention,parts being broken away and in section to illustrate details ofconstruction;

FIG. 2 is a side elevational view of one of the reactor plates of theozone generator of FIG. 1;

FIG. 3 is an enlarged, fragmentary, side elevational view of one of thereactor plates;

FIG. 4 is an enlarged, cross-sectional exploded view of a pair of platesused to construct a reactor plate;

FIG. 5 is a cross-sectional view of a completed reactor plate;

FIG. 6 is an enlarged, fragmentary, top plan view of a mount for one ofthe group of reactor plates of the ozone generator;

FIG. 7 is a cross-sectional view of a fitting forming a part of one ofthe mounts;

FIG. 8 is a fragmentary, cross-sectional view of one of the reactorplates, showing the way in which a pair of fittings of one of the mountsare coupled to the plate.

FIG. 9 is a view similar to FIG. 8 but showing another embodiment of apair of fittings attached to a reactor plate; and

FIG. 10 is a block diagram of a system utilizing the ozone generator anda refrigeration system for directing a coolant through the reactorplates to cool the same.

The ozone generator of this invention is broadly denoted by the numeral10 and includes a housing 12 within which is mounted an assembly 14 ofreactor plates which are spaced apart and between which ozone isgenerated when an electric field is established between each pair ofadjacent plates. Assembly 14 is comprised of two groups of reactorplates, namely, a first group of plates 16 coupled by a pair of spaced,parallel mounts 18 to a pair of spaced, flat, parallel sides 20 ofhousing 12 and a second group of reactor plates 22 coupled by a pair ofspaced, parallel mounts 24 to sides 20. Plates 16 are interleaved withplates 22 as shown in FIG. 1. While only a pair of reactor plates 16 anda pair of plates 22 are shown and described herein, it is possible thatmore reactor plates 16 and 22 can be used in ozone generator 10, ifdesired. Mounts 18 and 24 are substantially parallel with each other.

Housing 12 presents a central closed space 25 in which plate assembly 14is removably mounted. To this end, mounts l8 and 24 are removablysecured to sides 20 and are assembled thereto as the housing isassembled. This permits each group of plates to be formed as a modularunit so that it can be leak-checked before being installed in housing12. To permit assembly of housing 12, the latter has a pair of first,parallel end walls 26 and a pair of second, parallel end walls 28, bothpairs of end walls spanning the distance between sidewalls 20. Sides 20can be of an electrically insulative material or means can be providedto electrically isolate mounts l8 and 24 from sides 20.

Housing 12 also includes a fluid inlet manifold adjacent to one of thesecond end walls 28 and a fluid outlet manifold 32 adjacent to the othersecond wall 28. Manifolds 30 and 32 have conduits 34 and 35 coupledthereto providing inlet and outlet paths, respectively, to and fromhousing 12.

A porous wall 36 is disposed between central closed space 25 of housing12 and inlet manifold 30. Wall 36 has a number of spaced holes 38therethrough by means of which air or oxygen entering inlet manifold 30through conduit 34 will be uniformly distributed into central space andthereby uniformly between the reactor plates of plate assembly 14. Inlieu of holes, wall 36 could be of sintered material.

Similarly, a porous wall 40 is provided at the junction of space 25 ofhousing 12 and outlet manifold 32. Thus, air and ozone within space 25can pass uniformly out of the same and into outlet manifold 32 for flowout of the latter through outlet conduit 35. Also, wall 40 provides asmall back-pressure in the spaces between plates 16 and 22 to facilitatethe uniform distribution of air in such spaces.

Reactor plates 16 and 22 are substantially identical with each other.Each plate, as shown in FIG. 2, has a pair of spaced ears 46 extendinglaterally from a side margin 47 near opposed ends of the plate. Each earhas a hole 48 (FIG. 3) therethrough. For purposes of illustration, eachplate is formed from a pair of initially flat, relatively thin metallicplates 50 and 52 (FIG. 4) having elongated recesses 54 and 56 formedtherein, such as by etching, milling and the like, there being a numberof such recesses in each thin plate, respectively. When plates 50 and 52are bonded together at their outer marginal edges. recesses 54 and 56mate with each other and form a plurality of independent, fluid passages58 through the resulting reactor plate, each passage 58 extending fromone hole 48 to the opposite hole 48 as shown in dashed lines in FIG. 2.Also, each fluid passage 58 is in fluid communication with holes 48 bymeans of slots 86 (FIGS. 8 and 9).

Plates 50 and 52, for instance, are in the range of 10 to mils inthickness and are preferably brazed together to provide the necessaryrigidity, dimensional tolerance and heat transfer capability. The depthof the fluid passage is of the order of 5 to 20 mils in thicknessdepending upon the degree of cooling desired, so that proper heattransfer will be established between the plates and a coolant flowingthrough passage 58 to cool the plates. Other configurations of the fluidpassage in each reactor plate can be used, if desired.

As shown in FIG. 5, each reactor plate 16 or 22 has a ceramic coating 70thereon to provide a dielectric therefor, the coating being on theentire outer surface of each reactor plate except for an annular region69 (FIG. 3) surrounding each hole 48, respectively, on opposed sides ofthe plate. Thus, regions 69 of each hole permit electrical contact withthe reactor plate by the corresponding mount. The ceramic material, forinstance. is porcelain having a high dielectric constant material, suchas titanium oxide. The coating is of uniform thickness and free fromcracks.

Mountings l8 and 24 are all of substantially the same basicconstruction. Each mounting is tubular and is of metal so that it iselectrically conductive. This allows one of mountings 18 to serve as afirst electrode and one of mountings 24 to serve as the secondelectrode, the electrodes to be coupled to an electrical power source71.

As shown in FIG. 6, each mounting is comprised of a first fitting 72spanning the distance between and coupled with adjacent reactor platesand a pair of end fittings 78 and 80 on the outer faces of the reactorplates. In one form of the mount, the fittings are rigidly secured toand in electrical contact with the metallic portion 69 (FIG. 3) of eachplate (FIG. 9) such as by welding or brazing. This assures a permanentconnection of the mount to the plate and one which can be leak-testedbefore being assembled to housing 12.

In another form of the mount, the fittings are not welded or brazed tothe metallic portions 69 of the plates but are held in engagementtherewith by threaded fasteners, such as nuts threaded onto the outerfittings 78 and 80 and engaging housing sides 20. Thus, the fittings canbe separated from each other to facilitate replacement of reactor platesyet the mounts and reactor plates can be leak-tested before beingassembled to housing 12.

In the latter embodiment, each fitting 72a has a pair of opposed annularrecesses 74 in the end faces thereof (FIG. 7) surrounding the centralpassage 76 therethrough. Recesses 74 are adapted to receive O-rings(FIG. 8) for sealing the junction between fittings 72a and plates 16 atthe ends of the fittings. Similarly, end fittings 78a and 80a have thesame end face configuration as fitting 72a for engaging thecorrespondingside of the plate 16. Fittings 78 and 80 of mounts 18 and24 pass through sides 20 of housing 12 for mounting reactor platesthereon. Each fitting 78 is closed at one end thereof, such as by an endcap 79.

Each fitting 80 is coupled to a refrigeration system 82 (FIG. 10) sothat the refrigerant of such system will flow into passages 58 of thereactor plates in heat exchange relationship thereto. For instance, forplates 16, the refrigerant will pass from a first mount 18 into and 86of plates 16, through passages 58 thereof, andn out of the other slots86 to the opposite mount 18. For this case, plates 16 and 18 define theevaporator for the refrigeration system.

To assemble ozone generator 10, the two groups of plates 16 and 22 arecoupled to sides 20 of housing 12. Then the remaining walls 26, 28, 36and 40 of the housing are then assembled to sides 20 to enclose theplates and also to form the inlet and outlet manifolds 30 and 32. One ofthe mounts 18 is coupled to one side of power source 71 and one of themounts 24 is coupled to the other side of the power source. Also, acoolant or refrigerant entering one fitting of a group of plates willflow through the two or more plates of the group and then out of suchplates through the other fitting of the corresponding group. When ozonegenerator 10 is assembled, the high tension plates, either plates 16 or22, extend beyond the grounded plates a sufficient distance so thatarc-over from side effects is eliminated.

The creep distance of ozone generator 10 is the distance from a plate 16along one of its mounts 18 to an adjacent side 20, then through the side20 to the next adjacent mount 24, and along the latter mount to the nextadjacent plate 22. This distance is quite long, of the order of severalinches.

In operation, the pressure side of refrigeration system 82 is coupled toone of the mounts 18 and one of the mounts 24 so that coolant can flowinto such mounts and into passages 58 of respective plates 16 and 22.The reservoir side of refrigeration system 82 is coupled to the othermounts l8 and 24 for receiving the coolant after the latter has passedin heat exchange relationship through passages 58 of the reactor platesto cool the same. With an electrical power source coupled as shown inFIG. 1, electrical field intensities are established between adjacentreactor plates.

With air or oxygen directed under pressure into inlet maniford 30 andwith an electrical field established between the plates, the air oroxygen will pass through openings 38 of porous wall 36 and into space 25between adjacent reactor plates so as to be ionized to form ozone. Whengenerated, the ozone moves out of the housing, through the holes inporous wall 40, into outlet manifold 32 and then out of the same throughconduit 35 for collection in any suitable manner at a remote location.During the generation of ozone, the coolant or refrigerant flowingthrough passages 58 will keep the plates at a relatively low temperatureto assure optimum generation of ozone inasmuch as the air temperaturebetween reactor plates, if elevated too high, will have an adverseeffect on the generation of ozone.

The present invention provides and assures for optimum and efficientgeneration of ozone inasmuch as substantially all of the reactor platesurfaces are available for ozonation. Also, the method of thefabrication of each plate allows for maximum cooling in a minimum ofspace. This is possible because fluid passages 58 can be of a suitabledepth to provide strength for each plate yet permit the coolant to bedirected very closely to the working surfaces of the plates.

The reactor plates are easily accessible and can be replaced merely bydisassembling the housing and separating the plate groups from thehousing. The ability to completely test and leak-check a group ofreactor plates before insertion in the system is another feature whichrenders the present invention readily adapted for efficient productionof ozone. Because the dielectric is a coating on the plates, thisassures that the absence of any dielectric support within the coronadischarge zone will extend electrode life free from dielectric spacersurface contamination and eventual breakdown.

Refrigeration system 82 also includes a compressor 112, a condensingunit 114 cooled by water which is passed into and out of the same, andan expansion valve 116 provided in the outlet line 118 from thecondensing unit 114 to ozone generator 10. Line 118 is coupled to one ofthe mounts l8 and one of the mounts 24. The inlet line 120 to thecondensing unit is coupled to the other mount 18 and 24. Freon 12 is therefrigerant used in system 82.

It is desirable to construct the reactor plates in a manner such thatfor a given volume rate of flow of Freon into the plates approximately15 percent of the Freon leaving the reactor plates and moving toward thecompressor is in a liquid state and the remaining 85 percent is in thegaseous state. The liquid Freon has further cooling capability and thatcapability is used to pre-cool the air entering the ozone generator. Tothis end, the Freon is directed through a heat exchanger 121 in serieswith compressor 112. The incoming air moving toward ozone generator isdirected through heat exchanger 121 and is cooled before entering ozonegenerator 10. This causes the liquid Freon to vaporize and to enhancethe overall system efficiency.

The use of the refrigerant as a coolant minimizes the size and thecomplexity of the system, including the reactor plates, inasmuch as thereactor plates substitute as an evaporator of the refrigerant systemitself. Moreover, Freon is a more effective heat transfer fluid than oilor water.

In operation, a typical set of parameters for system 82 is as follows:The ozone generating capacity is pounds per day. The surface density ofthe reactor plates 16 and 22 is 1000 watts per square foot. Dry air isfed into ozone generator 10 at 68F. The power dissipated in the systemis 5 to 8 kilowatt hours per pound of ozone generated. The appliedvoltage to the high tension reactor plates is 7,000 to 12,000 volts rmsat a frequency of 2,00020,000 Hz. The refrigerant is Freon 12 andcooling requirements are percent of total power. The dielectricthickness, i.e., the thickness of coating 70, is about 0.012 inch andthe discharge gap between a pair of reactor plates is 0.05 to 0.09 inch.

Plates 16 and 22 are spaced from each other and are essentiallycantilevered relative to each other. Thus, there are no connecting postsor dielectrics between adjacent plates so that the creep distance issubstantially infinite to prevent arc-over therebetween. Thus, theplates can be nested quite closely to each other to provide a neat,compact assembly. This feature permits housing 12 to be of relativelysmall size yet the production of ozone is optimized, notwithstanding thecompact nature of the plate assembly. Also, the fact that all of theplates of the assembly can be internally cooled assures optimal ozoneproduction because the production rate of ozone decreases as airtemperatures in the spaces between the plates increases.

The advantage of using a plurality of fluid passages 58 in each reactorplate assures that the refrigerant paths through each plate are ofminimum distance. Thus, the pressure drop along each refrigerant path isminimized, thereby making the use of a refrigeration system feasible foruse in cooling reactor plates of an ozone generator. Otherwise, if thefluid paths 58 were longer, such as a single, serpentine fluid pathbetween holes 48 or a reactor plate, there would be an extremely highpressure drop along such path, requiring inlet fluid pressures possiblyso high that the plate itself would rupture. in the present invention,the internal fluid pressures in the reactor plates are kept to a minimum, thereby avoiding this problem.

What is claimed is:

1. An ozone generator comprising: a housing having a fluid inlet end anda fluid outlet end; an assembly of reactor plates, each plate havingfluid passage means therethrough and a coating of ceramic materialcovering substantially the entire outer surface thereof to define adielectric therefor; means mounting said assembly within said housingwith said reactor plates thereof in interleaved, spaced, cantilevered,relationship with each other and with the mounting means dividing theassembly into two groups of plates, said mounting means including a pairof tubular mounts for each group, respectively, at least one of themounts of each group being electrically conductive and in electricalcontact with the corresponding reactor plates, said mounts being influid communication with the passage means of corresponding reactorplates and adapted to be coupled to a source of coolant, whereby acoolant can be directed into said passages and thereby into heatexchange relationship with said reactor plates; and air distributionmeans adjacent to the inlet end of said housing for permitting a fluidto flow substantially uniformly into the spaces between said plates, theozone produced in said spaces being movable out of said housing throughsaid outlet end.

2. An ozone generator as set forth in claim 1, wherein each pair ofmounts are rigidly coupled to the reactor plates of a respective groupto form a modular unit, the modular units being removably secured tosaid housing.

3. An ozone generator as set forth in claim 1, wherein each mountincludes a first fitting between each pair of adjacent reactor plates ofa corresponding group, and second fittings extending outwardly from thereactor plates at the outer ends of each group.

4. An ozone generator as set forth in claim 3, wherein said fittings arerigidly secured to respective plates.

5. An ozone generator as set forth in claim 3, wherein said fittings areremovably coupled to respective plates, each fitting having at least oneplate-engaging end face provided with an annular recess therein, and anO-ring seal in said recess for sealing the junction between thecorresponding fitting and the adjacent reactor plate.

6. An ozone generator as set forth in claim 1, wherein each reactorplate has a pair of spaced holes therethrough, each mount being coupledto a corresponding plate at one of the holes thereof, the fluid passagein each reactor plate being in fluid communication with the holesthereof.

7. An ozone generator as set forth in claim 6, wherein each reactorplate has an annular, ceramic-free portion surrounding each hole,respectively, on each side thereof, each mount including a pair ofelectrically conductive, tubular fittings engaging respective annularportions.

8. An ozone generator as set forth in claim 1, wherein said housing hasa pair of fluid manifolds adjacent to the inlet and outlet ends thereof,respectively, and a porous wall between each manifold and the interiorof said housing.

9. An ozone generator as set forth in claim 8, wherein said wall has anumber of spaced holes therethrough.

10. An ozone generator as set forth in claim 8, wherein said wall isformed from a sintered material.

11. An ozone generator as set forth in claim 1, wherein each reactorplate has a number of spaced fluid passages therethrough.

12. An ozone generator as set forth in claim 11, wherein each reactorplate has a pair of spaced holes therethrough, each pair of mounts beingcoupled to corresponding reactor plates at respective holes thereof, thefluid passages in each plate extending between respective holes andbeing fluid communication with each other.

13. An ozone generator as set forth in claim 1, wherein each reactorplate has a pair of opposed side margins, there being a pair of earsrigid to and extending laterally from one of the side margins, each earhaving a hole therethrough, each hole being in fluid communication withthe corresponding fluid passage, each pair of mounts being secured tothe corresponding plates in fluid communication with respective holesthereof, the ears of each group of plates being aligned with each other,the ears of one group of plates being adjacent to one extremity of saidhousing and the ears of the other group of plates being adjacent to theopposite extremity of the housing.

14. An ozone generator comprising: a housing having a pair of spaced,opposed sides defining a platereceiving space therebetween, a fluidinlet manifold at one end thereof, and a fluid outlet manifold at theopposite end thereof, there being a porous wall between said space andeach manifold, respectively; a pair of groups of reactor plates, eachplate having a plurality of fluid passages therethrough and a coating ofceramic material covering the entire outer surface thereof; and a pairof tubular mounts for each group of reactor plates, respectively, eachpair of mounts being coupled to respective reactor plates and secured toand spanning the distance between the sides of the housing to cause thereactor plates thereof to be cantilevered with respect thereto, thereactor plates of one group being interleaved with and spaced from thereactor plates of the other group, each mount being in fluidcommunication with the fluid passages in respective reactor plates, atleast a first of the mounts of each group being in electrical contactwith the corresponding reactor plates, whereby the first mounts of saidgroups can be coupled to a source of electrical power, said mountsadapted to be coupled to a source of coolant to permit the coolant topass through said fluid passages and in heat exchange relationship tosaid reactor plates.

15. An ozone generator as set forth in claim 14, wherein is included arefrigeration system having a quantity of a refrigerant and being influid communication with said mounts, whereby the refrigerant can flowthrough said plates in heat exchange relationship thereto to cause theplates to form the evaporator of said system.

16. An ozone generator comprising: a housing; a plurality of spaced,interleaved reactor plates in the housing, each plate having fluidpassage means therethrough; coating means on said plates for defining adielectric between each pair of adjacent plates; and a refrigerationsystem in fluid communication with the fluid passage means of eachreactor plate, said reactor plates defining the evaporator of thesystem, there being a refrigerant in said system for cooling saidreactor plates.

17. An ozone generator as set forth in claim 16, wherein said housinghas means for directing air into the spaces between said reactor plates,said refrigeration system including means for pre-cooling the airdirected toward said spaces.

18. An ozone generator as set forth in claim 17, wherein saidrefrigeration system includes a compressor, said pre-cooling meansincluding a heat exchanger between said compressor and said housing, thevolume rate of How of refrigerant through the system being sufficient tocause a portion of the refrigerant passing into the heat exchanger fromthe reactor plates to be in a liquid state.

19. An ozone generator as set forth in claim 16, wherein said housinghas a fluid inlet end, and including fluid distribution means adjacentto said inlet end for permitting a fluid to flow substantially uniformlyinto and out of the same, each reactor plate having a plurality of fluidpassage therethrough.

20. An ozone generator as set forth in claim 16, wherein each reactorplate has a coating of ceramic material covering the entire outersurface thereof, said coating defining said dielectric means.

21. An ozone generator as set forth in claim 16, wherein is included thereactor plates which are arranged in two groups, each group having apair of tubular mounts for coupling the corresponding plates to thehousing, at least one of the mounts of each group being electricallyconductive and in electrical contact with the corresponding plates, themounts of each group placing the plates in fluid communication with saidrefrigeration system.

22. An ozone generator as set forth in claim 21, wherein the plates ofeach group are cantilevered with respect to the corresponding mounts.

23. An ozone generator comprising: a housing; a plurality of reactorplates, each plate having a plurality of tive mounts, at least one ofthe mounts of each group being electrically conductive and in electricalcontact with the corresponding reactor plates, said mounts being influid communication with the passages of corresponding reactor plates;and a refrigeration system in fluid communication with said mounts andhaving a refrigerant for cooling said reactor plates, the latterdefining the evaporator for said refrigeration system.

1. An ozone generator comprising: a housing having a fluid inlet end anda fluid outlet end; an assembly of reactor plates, each plate havingfluid passage means therethrough and a coating of ceramic materialcovering substantially the entire outer surface thereof to define adielectric therefor; means mounting said assembly within said hOusingwith said reactor plates thereof in interleaved, spaced, cantilevered,relationship with each other and with the mounting means dividing theassembly into two groups of plates, said mounting means including a pairof tubular mounts for each group, respectively, at least one of themounts of each group being electrically conductive and in electricalcontact with the corresponding reactor plates, said mounts being influid communication with the passage means of corresponding reactorplates and adapted to be coupled to a source of coolant, whereby acoolant can be directed into said passages and thereby into heatexchange relationship with said reactor plates; and air distributionmeans adjacent to the inlet end of said housing for permitting a fluidto flow substantially uniformly into the spaces between said plates, theozone produced in said spaces being movable out of said housing throughsaid outlet end.
 2. An ozone generator as set forth in claim 1, whereineach pair of mounts are rigidly coupled to the reactor plates of arespective group to form a modular unit, the modular units beingremovably secured to said housing.
 3. An ozone generator as set forth inclaim 1, wherein each mount includes a first fitting between each pairof adjacent reactor plates of a corresponding group, and second fittingsextending outwardly from the reactor plates at the outer ends of eachgroup.
 4. An ozone generator as set forth in claim 3, wherein saidfittings are rigidly secured to respective plates.
 5. An ozone generatoras set forth in claim 3, wherein said fittings are removably coupled torespective plates, each fitting having at least one plate-engaging endface provided with an annular recess therein, and an O-ring seal in saidrecess for sealing the junction between the corresponding fitting andthe adjacent reactor plate.
 6. An ozone generator as set forth in claim1, wherein each reactor plate has a pair of spaced holes therethrough,each mount being coupled to a corresponding plate at one of the holesthereof, the fluid passage in each reactor plate being in fluidcommunication with the holes thereof.
 7. An ozone generator as set forthin claim 6, wherein each reactor plate has an annular, ceramic-freeportion surrounding each hole, respectively, on each side thereof, eachmount including a pair of electrically conductive, tubular fittingsengaging respective annular portions.
 8. An ozone generator as set forthin claim 1, wherein said housing has a pair of fluid manifolds adjacentto the inlet and outlet ends thereof, respectively, and a porous wallbetween each manifold and the interior of said housing.
 9. An ozonegenerator as set forth in claim 8, wherein said wall has a number ofspaced holes therethrough.
 10. An ozone generator as set forth in claim8, wherein said wall is formed from a sintered material.
 11. An ozonegenerator as set forth in claim 1, wherein each reactor plate has anumber of spaced fluid passages therethrough.
 12. An ozone generator asset forth in claim 11, wherein each reactor plate has a pair of spacedholes therethrough, each pair of mounts being coupled to correspondingreactor plates at respective holes thereof, the fluid passages in eachplate extending between respective holes and being fluid communicationwith each other.
 13. An ozone generator as set forth in claim 1, whereineach reactor plate has a pair of opposed side margins, there being apair of ears rigid to and extending laterally from one of the sidemargins, each ear having a hole therethrough, each hole being in fluidcommunication with the corresponding fluid passage, each pair of mountsbeing secured to the corresponding plates in fluid communication withrespective holes thereof, the ears of each group of plates being alignedwith each other, the ears of one group of plates being adjacent to oneextremity of said housing and the ears of the other group of platesbeing adjacent to the opposite extremity of the housing.
 14. An ozonegenerator comprising: a housing having a pair of spaced, opposed sidesdefining a plate-receiving space therebetween, a fluid inlet manifold atone end thereof, and a fluid outlet manifold at the opposite endthereof, there being a porous wall between said space and each manifold,respectively; a pair of groups of reactor plates, each plate having aplurality of fluid passages therethrough and a coating of ceramicmaterial covering the entire outer surface thereof; and a pair oftubular mounts for each group of reactor plates, respectively, each pairof mounts being coupled to respective reactor plates and secured to andspanning the distance between the sides of the housing to cause thereactor plates thereof to be cantilevered with respect thereto, thereactor plates of one group being interleaved with and spaced from thereactor plates of the other group, each mount being in fluidcommunication with the fluid passages in respective reactor plates, atleast a first of the mounts of each group being in electrical contactwith the corresponding reactor plates, whereby the first mounts of saidgroups can be coupled to a source of electrical power, said mountsadapted to be coupled to a source of coolant to permit the coolant topass through said fluid passages and in heat exchange relationship tosaid reactor plates.
 15. An ozone generator as set forth in claim 14,wherein is included a refrigeration system having a quantity of arefrigerant and being in fluid communication with said mounts, wherebythe refrigerant can flow through said plates in heat exchangerelationship thereto to cause the plates to form the evaporator of saidsystem.
 16. An ozone generator comprising: a housing; a plurality ofspaced, interleaved reactor plates in the housing, each plate havingfluid passage means therethrough; coating means on said plates fordefining a dielectric between each pair of adjacent plates; and arefrigeration system in fluid communication with the fluid passage meansof each reactor plate, said reactor plates defining the evaporator ofthe system, there being a refrigerant in said system for cooling saidreactor plates.
 17. An ozone generator as set forth in claim 16, whereinsaid housing has means for directing air into the spaces between saidreactor plates, said refrigeration system including means forpre-cooling the air directed toward said spaces.
 18. An ozone generatoras set forth in claim 17, wherein said refrigeration system includes acompressor, said pre-cooling means including a heat exchanger betweensaid compressor and said housing, the volume rate of flow of refrigerantthrough the system being sufficient to cause a portion of therefrigerant passing into the heat exchanger from the reactor plates tobe in a liquid state.
 19. An ozone generator as set forth in claim 16,wherein said housing has a fluid inlet end, and including fluiddistribution means adjacent to said inlet end for permitting a fluid toflow substantially uniformly into and out of the same, each reactorplate having a plurality of fluid passage therethrough.
 20. An ozonegenerator as set forth in claim 16, wherein each reactor plate has acoating of ceramic material covering the entire outer surface thereof,said coating defining said dielectric means.
 21. An ozone generator asset forth in claim 16, wherein is included the reactor plates which arearranged in two groups, each group having a pair of tubular mounts forcoupling the corresponding plates to the housing, at least one of themounts of each group being electrically conductive and in electricalcontact with the corresponding plates, the mounts of each group placingthe plates in fluid communication with said refrigeration system.
 22. Anozone generator as set forth in claim 21, wherein the plates of eachgroup are cantilevered with respect to the corresponding mounts.
 23. Anozone generator comprising: a housing; a plurality of reactor plates,each plate having a plurality of fluid pasSages therethrough and acoating of ceramic material covering the entire outer surface thereof todefine a dielectric therefor; means mounting said reactor plates withinsaid housing and in interleaved, spaced relationship with respect toeach other with the mounting means dividing the reactor plates into twogroups, said mounting means including a pair of tubular mounts for eachgroup of reactor plates, respectively, the reactor plates beingcantilevered relative to respective mounts, at least one of the mountsof each group being electrically conductive and in electrical contactwith the corresponding reactor plates, said mounts being in fluidcommunication with the passages of corresponding reactor plates; and arefrigeration system in fluid communication with said mounts and havinga refrigerant for cooling said reactor plates, the latter defining theevaporator for said refrigeration system.